1. Field of the Invention
The present invention relates to a power semiconductor device in which a power semiconductor module is used, and particularly to a power semiconductor device, with a reduced size, which is excellent in terms of productivity.
2. Description of the Background Art
Power semiconductor devices are required to be reduced in size and operate with a large current. One of the methods for realizing such large-current operation is to wire power semiconductor modules of the same capacity in parallel to each other, thereby realizing large-current operation.
In an existing method for reducing the size of a power semiconductor device, a power semiconductor module sealed with transfer molding resin is used. Among such power semiconductor modules sealed with transfer molding resin, a power semiconductor module that particularly realizes the size reduction is the one in which: power semiconductor elements are mounted on a circuit pattern of a circuit substrate; terminals for connecting to external wiring are joined to the circuit pattern so as to be substantially perpendicular to a surface of the circuit pattern; and the terminals are exposed at a surface of the transfer molding resin.
A copper block, a cylinder having a screw hole, and a nut fixed by resin molding, are each used for a terminal of the power semiconductor module. The terminal that is a copper block is connected to the external wiring by soldering. The terminal that is a cylinder having a screw hole, or the terminal in which a nut is fixed by resin molding, is connected to the external wiring by a bolt (see, e.g., Page 7 and 8, FIGS. 2 and 3 of Japanese Laid-Open Patent Publication No. 2007-184315 (hereinafter, referred to as Patent Document 1)).
In the case where such power semiconductor modules as described in Patent Document 1 are wired in parallel in order to realize large-current operation, wiring components between the power semiconductor modules are connected by soldering or bolts. For this reason, it is necessary to perform connection of the wiring components for each power semiconductor module sequentially. Also, in each power semiconductor module, connection of a wiring component needs to be performed for each one of the multiple terminals provided therein.
Thus, since the connection is performed for each power semiconductor module and for each of the multiple terminals, the number of wiring components for the connections is large, and connection processes are complex and the number of connection processes is large. This results in low productivity of the power semiconductor device, causing a high cost. Further, space is necessary between the power semiconductor modules in order to perform an operation of connecting the wiring components. This results in having a wide space between the power semiconductor modules, causing a problem that the power semiconductor device becomes large-sized.